sort() and sort_multipv() are almost the same, so
use only one implementation.
Also introduce the natural RootMove::operator<() to
compare the moves instead of compare_root_moves(),
this will allow to use std::sort instead of our
home grown bubble-sort.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Moves are already sorted, so just consider the best
and the second one.
Some trailing whitespace remove noise crept in due
to my editor removes it before to save.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>